It is well known to provide portable apparatus, such as mobile or cellular telephones, with speaker arrangements. A speaker arrangement comprises a transducer located within a mechanical environment. Speaker arrangements in such devices tend to be designed to be optimised for a particular requirement. The frequency response of speaker devices are determined largely by physical dimensions of the mechanical arrangement of the speaker arrangement devices, and by properties of the transducer. Physical dimensions of the mechanical arrangement are chosen by a designer so as to achieve a desired frequency response.